Proximity payment cards or devices are in widespread use. A well known standard for such cards has been promulgated by MasterCard International Incorporated, the assignee hereof, and is referred to as “PayPass”. Proximity payment devices typically include a radio frequency identification (RFID) integrated circuit (IC) embedded in a card-shaped plastic body. An antenna is also embedded in the card body. The antenna allows the device to receive a power signal from a point of sale terminal. The antenna is also used by the RFID IC to transmit the payment device account number, and possibly other information as well, to a point of sale (POS) terminal.
It has been proposed to include in a proximity payment card a switch that may be actuated by being pressed by the cardholder's finger. Actuation of the switch may complete a circuit between the RFID IC and the antenna to allow the card to receive the power signal from the POS terminal. With this arrangement, the card is normally disabled (i.e., when the switch is not actuated), but can be enabled by actuating the switch when it is desired to present the card to the POS terminal. Because the card is normally disabled, it may be immune from attempts to surreptitiously interrogate the card in order to obtain the payment card account number for fraudulent purposes.
Unfortunately, many switching arrangements proposed for use in such proximity payment devices require modification of the RFID IC (e.g., such as to incorporate contacts and circuits for a switch). For example, many PayPass chips are becoming increasingly small in size and it is difficult to reliably or cost-effectively attach the antenna connections. Adding additional connections can be difficult and expensive. Further, many switching technologies suitable for inclusion in the body of a card do not provide a perfect on/off function. In their “off” state, some power and signal may pass through the switch sufficient to power the RFID device. In their “on” state, there may be power or signal degradation which significantly reduces the operating range of the RFID device.
It would be desirable to provide a switching mechanism that is separate from the RFID IC, allowing improved switch control using existing RFID ICs and technology.